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Font for digits lets numbers punch their weight

By Jacob Aron

Sicily in number font with mount Etna in the north-east

(Image: M. Nacent/U. Hinrichs/S. Carpendale)

THE symbols we use to represent numbers are, mathematically speaking, arbitrary. Now there is a way to write numbers so that their areas equal their numerical values. The font, called FatFonts, could transform the art of data visualisation, allowing a single infographic to convey both a visual overview and exact values.

“Scientific figures might benefit from this hybrid nature because scientists want both to see and to read data,” says Miguel Nacenta, a computer scientist at the University of St Andrews, UK, who developed the concept with colleagues at the University of Calgary, Canada.

The hybrid nature of this font would allow scientists to both see and read data displayed in graphics

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Infographics are all the rage as a means to display information now that computers can gather and sort vast reams of data. However, fancy charts and images often obscure the actual data behind them. To get the best of both worlds, Nacenta’s team designed a font in which a 2 has an area exactly twice that of a 1, a 3, triple, and so on.

For single digit numbers, this was fairly straightforward. The team measured the area of each number and then thickened or thinned sections of it so that the total area scaled in proportion to each number’s value. A digit like 2 did not need much thickening as it already covers a larger area than 1. By contrast 7 needed a lot of thickening as its total area is small relative to its value.

To represent numbers with multiple digits, the team devised a system of nested digits. In the case of 489, the 8 sits inside the 4 and covers an area 10 times smaller, while the 9 sits inside the 8 and covers an area 10 times smaller still. This makes 999 the largest number possible with FatFonts, as the smallest part of a four digit number would be too little to see easily.

To demonstrate the usefulness of the concept, Nacenta’s team used FatFonts to create a map of Sicily in which each number represents the height of the ground at that geographical location (see images). For easy reading they scaled the heights so that the largest is represented by the number 99.

As with existing heat maps, where areas associated with larger numbers appear proportionally darker, standing back from the map makes it easy to identify mountainous regions. However, the FatFonts map has the added advantage that moving closer lets you compare points numerically, too. FatFonts are most effective when printed on large, high-resolution wall displays, says Nacenta. These are big enough to see the individual numbers, as well as larger-scale trends.

“It is a clever way of using numbers for visualisation,” says Robert Kosara, an information visualisation researcher at the University of North Carolina at Charlotte, although he suspects FatFonts could be misleading in some cases. “The next step is to run a user study and compare it to a heat map and other techniques.”

Nacenta’s team will present their work at the Advanced Visual Interfaces conference in Naples, Italy, later this month. “We are hoping that typeface designers and other people will pick up on our idea and create their own versions,” says Nacenta.